No reports have yet been published on catatonia using latent class analysis (LCA). This study applied LCA to a large, diagnostically homogenous sample of patients with chronic schizophrenia who also presented with catatonic symptoms. A random sample of 225 Chinese inpatients with DSM-IV schizophrenia was selected from the long-stay wards of a psychiatric hospital. Their psychopathology, extrapyramidal motor status and level of functioning were evaluated with standardized rating scales. Catatonia was rated using a modified version of the Bush-Francis Catatonia Rating Scale. LCA was then applied to the 178 patients who presented with at least one catatonic sign. In LCA a four-class solution was found to fit best the statistical model. Classes 1, 2, 3 and 4 constituted 18%, 39.4%, 20.1% and 22.5% of the whole catatonic sample, respectively. Class 1 included patients with symptoms of 'automatic' phenomena (automatic obedience, Mitgehen, waxy flexibility). Class 2 comprised patients with 'repetitive/echo' phenomena (perseveration, stereotypy, verbigeration, mannerisms and grimacing). Class 3 contained patients with symptoms of 'withdrawal' (immobility, mutism, posturing, staring and withdrawal). Class 4 consisted of 'agitated/resistive' patients, who displayed symptoms of excitement, impulsivity, negativism and combativeness. The symptom composition of these 4 classes was nearly identical with that of the four factors identified by factor analysis in the same cohort of subjects in an earlier study. In multivariate regression analysis, the 'withdrawn' class was associated with higher scores on the Scale of Assessment of Negative Symptoms and lower and higher scores for negative and positive items respectively on the Nurses' Observation Scale for Inpatient Evaluation's (NOSIE). The 'automatic' class was associated with lower values on the Simpson-Angus Extrapyramidal Side Effects Scale, and the 'repetitive/echo' class with higher scores on the NOSIE positive items. These results provide preliminary support for the notion that chronic schizophrenia patients with catatonic features can be classified into 4 distinct syndromal groups on the basis of their motor symptoms. Identifying distinct catatonic syndromes would help to find their biological substrates and to develop specific therapeutic measures.

This study set out to determine the frequency of catatonic syndrome in chronic schizophrenia and its association with sociodemographic, clinical, and treatment variables. A cross-sectional assessment of a randomly selected cohort of patients (n=225; mean age=42+/-7 years; mean length of illness=20.4+/-7.5 years) with DSM-IV schizophrenia was employed using standard rating instruments for catatonia, drug-induced extrapyramidal symptoms (EPS), and psychotic, depressive, and obsessive-compulsive symptoms. Using a rather narrow definition of catatonia [the presence of four or more signs/symptoms with at least one having a score '2' or above on the Bush-Francis Catatonia Rating Scale (BFCRS)], 72 subjects (32%) met the criteria for the catatonia group (mean number of catatonic signs/symptoms=5.9+/-2.0; mean sum score of 8.7+/-3.4 on the BFCRS). The frequency distribution of catatonic signs/symptoms in the catatonic group and in the whole sample was very similar, with mannerisms, grimacing, stereotypes, posturing, and mutism being the most frequent. In the logistic regression analysis, catatonic subjects had a significantly earlier age of onset, more negative symptoms, and were more likely to receive benzodiazepines than their noncatatonic counterparts. In multiple regression analysis, the severity of catatonia as indicated by the sum score of BFCRS was predicted only by earlier age of onset and negative symptoms. Using relatively narrow criteria, this study confirmed that, if methodically assessed, catatonic signs and symptoms are prevalent in patients with chronic schizophrenia. Catatonia can be differentiated from EPS. Catatonic features indicate a generally poor prognosis in the chronic phase of schizophrenia.

The recent interest in biologically oriented psychiatry has opened up new opportunities for collaboration between psychiatry and neurology. Traditionally neurologists emphasized neuronal pathways and lateralizing signs, while psychiatrists' main interest was feeling states and emotions. Increasingly, both specialties are becoming aware of the complexity of the nervous system and the frequency with which neuronal disturbances and psychological conflict interact and influence treatment and outcome. The most important factor in facilitating an increased number of consultations and generating research protocols involves achieving a certain mutuality and complementary role between two disciplines. Traditionally there has been a fair amount of antagonism, primarily because of each specialty's insistence that its vantage point of view was correct. The consultation-liaison psychiatrist is in the ideal position to bring about a rapprochement. To achieve this, it is paramount that the psychiatrist understand and be conversant in the neurologist's language.